STI trends in 2017

As explained elsewhere here on, chlamydia is the most common STI in the UK.

But just how common is it? We thought it might be interesting to get together some figures from Public Health England to demonstrate how large a proportion of STIs in England chlamydia is responsible for.

Public Health England’s latest STI statistics were released at the beginning of June.

These show that in 2017 there were 422,147 new STI diagnoses made. Whilst the total number of new diagnoses has remained close to last year’s total of 423,352 the data has still caused quite a stir due to the evident increases in cases of gonorrhoea and syphilis.

STI diagnoses rates in England

According to the report the total number of STI diagnoses in 2008 was calculated at 415,837 which would indicate a ten year increase of 6,310 cases. However, the report does state that there have been some changes in how data is collected over the years, therefore the numbers cannot be directly compared.

The data that has drawn the most attention is that which shows the increase in cases of both gonorrhoea and syphilis. Let’s take a closer look at the two conditions:


The number of diagnosed gonorrhoea cases has gone up by over eight thousand in just one year to a total of 44,676. Gonorrhoea can usually be treated with a course of antibiotics. However, this particular increase has been reported to be all the more worrying due to drug resistant strains of the condition. The first case of Neisseria gonorrhoeae or ‘super-gonorrhoea’ was diagnosed in the UK in March 2018. This strain does not respond to the usual lines of treatment.

The potential for ‘super gonorrhoea’ to become a widespread health issue led the National Institute for Health and Care Excellence (NICE) to request all gonorrhoea cases be followed up with a test to prove that the infection has cleared up. This guidance has been in place for several years now.

What is syphilis and why is it on the increase?

The second biggest increase in diagnosed cases was seen in syphilis, which saw a jump from 5,955 in 2016 to 7,137 in 2017. This dramatic 20 per cent increase has caught the attention of the media, with some news outlets reporting that this is the biggest increase in cases since 1949.

Syphilis is a bacterial infection that can cause a number of symptoms including: genital or oral sores, tiredness, fever, headaches, joint pain and a rash. If left undetected the condition can progress to the brain and even be fatal.

The spike in syphilis numbers was almost exclusively seen in gay, bisexual or other men who have sex with men (or MSM).

Overall syphilis is still one of the lesser-seen STIs, making up around two per cent of the total STIs in England.

However, the reemergence of the disease, which was all but eradicated in the 1980s, has left STI specialists wondering about the possible causes behind this increase in numbers. It has been suggested that dating apps could be providing more opportunities for casual sex, as well as group sex. The report also refers to an upsurge in ‘chemsex’, which is the act of having sex whilst taking drugs such as crystal meth.

Who is most at risk of STIs?

According to the report there are several at-risk groups. The presence of which is said to highlight a remaining inequality in the provision of sexual health services. These groups include:

  • Young heterosexuals, aged between 15 and 24 years
  • Black ethnic minorities
  • And MSM.

The report refers to several PHE-funded resources that aim to improve sexual health information amongst these groups.

Which STI is most common in England?

Chlamydia is still the most prolific STI in England. The slight decline in chlamydia testing has been put down to a reduction in service provision. Testing for chlamydia is down 61 per cent since 2015, even though the recommendations include testing all young women when they access contraception. The number of chlamydia diagnoses have remained steady over the past three years.

STI prevention

The positive introduction of The National HPV Immunisation Programme has led to a significant drop in diagnoses of genital warts. Initially the injection was only rolled out to adolescent girls but has since been extended to include boys, and MSM who attend specialist sexual health clinics. Over time this addition should be reflected in a further drop in the numbers of genital warts being diagnosed.

Different STIs come with different symptoms and treatment. Not all STIs can be cured and some STIs can cause fertility problems.

The best way to avoid contracting a sexually transmitted infection is to practice safe sex. This involves the correct and consistent use of condoms and also regular STI screening for those at risk.

Many STIs can be symptomless which means that there could be a delay in receiving the necessary treatment. Sexually active people should look to be tested once every year or after having unprotected sex. Those who fall into at-risk groups may be advised to be tested more regularly.

If you have sexual health concerns or you want to arrange to be tested for STIs you should attend a GUM (genitourinary medicine) or sexual health clinic.

Page last reviewed:  11/05/2021